Cinder Carla. Pilot of AC: FULL COURSE. Leader of RaD and a brilliant engineer. She is an old acquaintance of Walter. She refers to 621 exclusively as "Visitor." She often sorties in FULL COURSE to rescue 621 when they are in danger. She takes pride in the fact that 621 managed to make Chatty chuckle. Female.

Chatty Stick. Pilot of AC: CIRCUS. An AI created by Carla who serves as her right hand and systems specialist. He refers to 621 exclusively as "Visitor." Indoors, he inhabits a miniaturized version of his AC, CIRCUS. Male.

Handler Walter. 621's operator. He usually provides support from a transport helicopter, but in certain situations, he pilots the manned Ibis-series AC HAL 826 developed by the Rubicon Research Institute. Male.

A C-Pulse Mutation, a Rubiconian. She established contact with 621 at the Watchpoint and communicates telepathically during missions. Thanks to a device Carla built, she is visible to Chatty, Carla, and Walter, and speaks quite normally. She calls 621 "Raven" and has slightly yandere tendencies. Like Walter, she protects 621; she can remote-control the unmanned Ibis-series AC frame EPHEMERA (unit name ECHO) and other Coral-based technology. Female.

Independent Mercenary Raven. Pilot of AC: LOADER 4. An old-generation augmented human who was saved from being discarded by Walter and now follows his orders. Female. She rarely shows emotion, but after re-surgery, she has regained some feelings. Walter calls her 621; Carla and Chatty call her Visitor; Ayre, other mercenaries, corporations, and the PCA call her Raven.